The present invention relates to an image forming apparatus and particularly relates to separation technology of recording material in a fixing device of an image forming apparatus.
An electrophotographic image forming apparatus, in general, includes a fixing device for fixing a toner image onto a recording material by giving heat and pressure to the toner image on the recording material by using a heat member and a pressing member.
In the fixing device of the image forming apparatus, due to the viscosity of the toner, which has been heated and melted, the recording material tends to adhere to the heating member. Thus, in order to separate the recording material from the heating member, a separator for separating the recording material after fixing operation from the heating member is used. With regard to the separator, a separation claw for mechanically exfoliating the leading edge of the recording material from the heating member is widely used. However there are problems that the separation claw hurts the surface of the heating member and deforms the recording material. Further the separation claw itself is deformed and results in deterioration of separation performance. Accordingly, the developments to solve these problems have been conducted.
Japanese Patent Application Publication No. 60-247672 and Japanese Patent Application Publication No. 2005-157179 have disclosed an air separator for blowing compressed air against the leading edge of the recording material.
The air separator disclosed in Japanese Patent Application Publication No. 60-247672 and Japanese Patent Application Publication No. 2005-157179 are effective as a separation device for solving the problems associated with the separation claw. However, a conventional air separator is not enough as a separator in the following points.
With regard to the width direction perpendicular to the conveyance direction of the recording material, when air emitting amount distribution is not appropriate, there is a problem that separation failure and flapping of the recording material occur.
When, conducting image formation by using a different type of structure of the fixing device, by using different operation modes of the image forming apparatus, and particularly conducting image formation onto different sizes of recording material, the air emitting amount distribution in the width direction of the recording material becomes different air emitting amount distributions. In a conventional art, the air emitting amount distribution has not been considered.
For example, Japanese Patent Application Publication No. 60-247672 disclosed an air separator having a plurality of nozzles disposed in width direction of the recording material, into one of the nozzle, air being supplied from an edge of a pipe. However, since the air emitting amount distribution becomes high in an end portion according to the structure, there is a problem that separation failure tends to occur.